///
// * jdbm LICENSE v1.00
// *
// * Redistribution and use of this software and associated documentation
// * ("Software"), with or without modification, are permitted provided
// * that the following conditions are met:
// *
// * 1. Redistributions of source code must retain copyright
// *    statements and notices.  Redistributions must also contain a
// *    copy of this document.
// *
// * 2. Redistributions in binary form must reproduce the
// *    above copyright notice, this list of conditions and the
// *    following disclaimer in the documentation and/or other
// *    materials provided with the distribution.
// *
// * 3. The name "jdbm" must not be used to endorse or promote
// *    products derived from this Software without prior written
// *    permission of Cees de Groot.  For written permission,
// *    please contact cg@cdegroot.com.
// *
// * 4. Products derived from this Software may not be called "jdbm"
// *    nor may "jdbm" appear in their names without prior written
// *    permission of Cees de Groot. 
// *
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// *    (http://jdbm.sourceforge.net/).
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// * THIS SOFTWARE IS PROVIDED BY THE ndbm PROJECT AND CONTRIBUTORS
// * ``AS IS'' AND ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT
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// * CEES DE GROOT OR ANY CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
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// * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
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// *
// * Copyright 2000 (C) Cees de Groot. All Rights Reserved.
// * Contributions are Copyright (C) 2000 by their associated contributors.
// *
// * $Id: PhysicalRowId.java,v 1.1 2000/05/06 00:00:31 boisvert Exp $
// 

//*************************************************************************
//**  Included in JDMB 1.0 port to SharpDBM;  11/2013 Cyrus Neah cneah@codingreal.com
//**  SharpDBM is an independent reimplementation of the JDBM 1.0 software library in C#  
//*************************************************************************

namespace SharpDBM.recman
{

///
// *  A physical rowid is nothing else than a pointer to a physical location
// *  in a file - a (block, offset) tuple.
// *  <P>
// *  <B>Note</B>: The fact that the offset is modelled as a short limits 
// *  the block size to 32k.
// 
	internal class PhysicalRowId
	{
	// offsets
		private const short O_BLOCK = 0; // long block
		private const short O_OFFSET = Magic.SZ_LONG; // short offset
		internal const int SIZE = O_OFFSET + Magic.SZ_SHORT;

	// my block and the position within the block
		internal BlockIo block;
		internal short pos;

//    *
//     *  Constructs a physical rowid from the indicated data starting at
//     *  the indicated position.
//     
		internal PhysicalRowId(BlockIo block, short pos)
		{
			this.block = block;
			this.pos = pos;
		}

	/// Returns the block number 
		internal virtual long getBlock()
		{
			return block.readLong(pos + O_BLOCK);
		}

	/// Sets the block number 
		internal virtual void setBlock(long @value)
		{
			block.writeLong(pos + O_BLOCK, @value);
		}

	/// Returns the offset 
		internal virtual short getOffset()
		{
			return block.readShort(pos + O_OFFSET);
		}

	/// Sets the offset 
		internal virtual void setOffset(short @value)
		{
			block.writeShort(pos + O_OFFSET, @value);
		}
	}

}